Abstract
Inner dynein arm (IDA), composed of a series of protein complex, is necessary to cilia and flagella bend formation and beating. Previous studies indicated that defects of IDA protein complex result in multiple morphological abnormalities of the sperm flagellum (MMAF) and male infertility. However, the genetic causes and molecular mechanisms in the IDAs need further exploration. Here we identified two loss-of-function variants of WDR63 in both MMAF and non-obstructive azoospermia (NOA) affected cohorts. WDR63 encodes an IDA-associated protein that is dominantly expressed in testis. We next generated Wdr63-knockout (Wdr63-KO) mice through the CRISPR-Cas9 technology. Remarkably, Wdr63-KO induced decreased sperm number, abnormal flagellar morphology and male infertility. In addition, transmission electron microscopy assay showed severely disorganized “9 + 2” axoneme and absent inner dynein arms in the spermatozoa from Wdr63-KO male mice. Mechanistically, we found that WDR63 interacted with WDR78 mainly via WD40-repeat domain and is necessary for IDA assembly. Furthermore, WDR63-associated male infertility in human and mice could be overcome by intracytoplasmic sperm injection (ICSI) treatment. In conclusion, the present study demonstrates that bi-allelic variants of WDR63 cause male infertility via abnormal inner dynein arms assembly and flagella formation and can be used as a genetic diagnostic indicator for infertility males.
Highlights
Infertility is a global human health concern and affects approximately 8%–12% of couples around the world[1,2]
To identify the potential Inner dynein arm (IDA)-associated variants in male infertility, we conducted whole-exome sequencing (WES) analyses in a distinct morphological abnormalities of the sperm flagellum (MMAF) cohort depend on variants frequency and functional annotation (Supplementary Fig. S1)
WDR63-associated male infertility could be rescued by intracytoplasmic sperm injection (ICSI) we aimed to evaluate whether the male infertility induced by WDR63 variants could be overcome by Assisted Reproductive Technology (ART)
Summary
Infertility is a global human health concern and affects approximately 8%–12% of couples around the world[1,2]. Male infertility, which accounts for half of all infertility cases, is generally manifested by reduced sperm count (oligozoospermia and azoospermia), reduced sperm motility (asthenozoospermia), or increased percentage of abnormal sperm morphology (teratozoospermia). With the wide application of high-throughput sequencing technologies, such as whole-exome sequencing (WES), a series of MMAF-associated genes have been identified through genetic studies and animal models. These studies are relevant for MMAF diagnostic value, clinical decision making, and appropriate genetic counseling[10,11,12,13]. Owing to high genetic heterogeneity, only approximately 60% of MMAF-affected cases are caused by previously identified
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